A balanced level of vitamin D has long been recognized as essential to health. Vitamin D appears to increase the efficiency of the intestines to absorb calcium and also mobilizes calcium from bone tissue when required. A deficiency in vitamin D leads to rickets, a debilitating bone disease while excessive intakes of vitamin D are toxic.
The skin is the major site of cholesterol production and humans acquire vitamin D through the natural action of ultraviolet light on the skin. 7-Dehydrocholesterol, which is unstable to ultraviolet light, is normally a precursor to cholesterol. However, ultraviolet light breaks open the B-ring of the 7-dehydrocholesterol molecule to generate previtamin D3, which spontaneously isomerizes over hours and days into vitamin D3, which is also known as cholecalciferol. An unknown proportion of the vitamin D from the skin is absorbed into the circulation. Vitamin D3 is not soluble in water, and in the circulation, there is a protein that specifically binds to and carries vitamin D and its metabolites. The advantage of ultraviolet exposure is that it is natural, and has no vitamin D toxicity associated with it. The disadvantage is that the availability of ultraviolet light is unreliable, and too much of it causes sunburn or skin cancer. At northern latitudes there is often not enough ultraviolet light intensity outdoors to generate previtamin D.
For biological activity, vitamin D must go through two metabolic steps. Vitamin D is metabolized by the liver to 25-hydroxyvitamin D [25(OH)D], which is measured in serum to reflect vitamin D nutritional status. 25-hydroxyvitamin D per se has little biological activity. The kidney metabolizes 25-hydroxyvitamin D into the active hormone, 1, 25-dihydroxyvitamin D, which affects calcium transport across cell membranes. The body, according to its mineral requirements, carefully regulates production and breakdown of 1,25-dihydroxyvitamin D to regulate plasma calcium concentrations. Very few foods naturally contain vitamin D. Mellanby, J Physiol (London) volume 52:1iii (1919), instituted the idea that an artificial supplement, cod-liver oil, contained an agent that prevented rickets; the agent became known as vitamin D. Most of the vitamin D in our food is supplementary, synthetic material, which is either in the form of vitamin D3, the form naturally produced in animals, or it can be vitamin D2, which is derived from a plant steroid. The term, vitamin D, refers to either the vitamin D2 or vitamin D3 forms.
Pediatric associations in Canada and the United States now strongly encourage starting vitamin D supplementation from birth onwards (Health Canada, Vitamin D supplementation for breastfed infants). Breast-feeding results in fewer infections and allergies during the first year of life compared to babies fed formula. Breast milk provides nearly optimal nutrition for newborns; however, it provides little vitamin D. Vitamin D has well-recognized effects on bone, but beyond that, better vitamin D nutrition during infancy is associated with less risk of other diseases that develop later in life. These disease reductions include less risk of juvenile diabetes, and schizophrenia (Hypponen, E., Laara, E., Reunanen, A., Jarvelin, M. R., and Virtanen, S. M. (2001) Lancet 358, 1500-1503) (McGrath, J., Saari, K., Hakko, H., Jokelainen, J., Jones, P., Jarvelin, M. R., Chant, D., and Isohanni, M. (2004) Schizophr. Res. 67, 237-245). However, because it is normally obtained through sun exposure instead of orally, vitamin D is the one nutrient that is most often deficient in breast milk (Centers for Disease Control, Vitamin D Expert Panel Meeting, Oct. 11-12, 2001 Atlanta, Ga. Final Report).
In 2005, the American Academy of Pediatrics issued a new policy statement concerning breast-feeding (American Academy Of Pediatrics Policy Statement 2005; Pediatrics 115; 496-506). One major change was that all breast-fed infants should receive 200 IU (5 mcg) of oral vitamin D drops daily, beginning during the first 2 months of life. The older recommendation had been that vitamin D supplementation should start at around 2 months of life. The latest American Academy of Pediatrics recommendation follows what Health Canada has been advising, that vitamin D supplementation should be from birth, with 400 IU (10 mcg) of vitamin D per day (Pediatrics 2005; 115; 496-506). Moreover, Health Canada recommends that infants in the north be given 800 IU (20 mcg) of vitamin D per day.
The need to provide vitamin D at an earlier age makes the problem of providing vitamin D nutrition more complicated. Smaller infants are more difficult to handle. Furthermore, breast-feeding mothers may not want to give their infants foreign liquids or compounds that are not natural for them to be taking. What makes the problem worse, is that the recommendations from pediatric societies and government bodies provide no detail or any method for exactly how to give vitamin D to the breast-feeding infant. They simply advise that parents should be giving vitamin D.
Existing products, approved in Canada and the United States for the purpose of infant vitamin D nutrition require the use of one-half to one mL of a detergent-solublized aqueous liquid emulsion. The liquid is either given directly into the mouth, or mixed into milk or to other food consumed by the infant. Instructions for administering vitamin D drops typically involve inserting the dropper containing the liquid product directly into the baby's mouth.
Parents of infants express great frustration about existing products and methods for providing infants with vitamin D, especially about the taste and the fact that infants often spit out at least some of the liquid. Direct administration of liquid vitamin D preparations is commonly done with an eyedropper, and with the infant lying on its back. One risk associated with direct administration of vitamin D solutions into the mouth is that infants can gag on, or inhale some of the liquid.
Vitamin D liquid drops usually contain other vitamins as well. One milliliter of these products contains 400 IU (10 mcg) of vitamin D. The aqueous vitamin D drops have only a 50-day shelf-life once the bottle is opened. They contain ingredients foreign to infant nutrition, and there are many complaints about the taste. One major problem is that infants spit out the 1 mL liquid vitamin drops. This creates a mess and the dose delivered to the infant is unreliable. For any therapeutic protocol, inconvenience, risk, and difficulty with administration result in lower compliance rates. Poor compliance results in under-dosing, and ineffective treatment. These factors also diminish nutrient supplementation with vitamin D. There are vitamin D drops available in oil, at 400 IU per drop in the United States (naturalhealthsupply.com). The vitamin D for this is dissolved in olive oil and/or corn oil and/or sesame or flax-seed oil. The problem with these is that the oils are comprised of long-chain unsaturated fatty-acid triglycerides that will become rancid with repeated opening of the container, they carry a flavor, and they have a greasy feel on a pacifier. Moreover, no product like this is advised for, nor advocated, nor used in any way for nutrition of the breast-feeding infant.
One prescription product contains vitamin D in an unspecified oil, (20,000 IU (500 mcg) per mL of oil). The method for use involves mixing two drops into to two drops in milk or mash. This is not a practical way to provide vitamin D for breast-fed infants younger than two months of age, because it presumes that nutrition is provided by some means other than the breast. Furthermore, this method is no different from what is done in North America with the 1-mL per day liquid vitamin drops that are administered to infants by mixing into milk or food by the same method.
U.S. Pat. No. 5,532,229, issued Jul. 2, 1996 to Vieth, Reinhold W., and Canadian Patent No. 2,122,431, issued Oct. 10, 2006 to Vieth, Reinhold W., describe a method of delivering vitamin D to the blood of a mammal by topically administering to the skin of the mammal, vitamin D in a solution. In principle, this method could be used to provide vitamin D to infants, via the skin, which is a safe and natural route of entry for this nutrient. For example, a skin lotion that contains vitamin D can be absorbed over time through the skin of the infant. For example, medium-chain triglycerides are useful as a skin lotion, and at the same time they can function as a solvent to deliver vitamin D. However, the efficacy of vitamin D delivery is problematic with this approach, because vitamin D could be wiped easily off the skin before it could be absorbed into the body.
U.S. Pat. No. 4,248,867, issued to Ikushima et al on Feb. 3, 1981 describes a method for manufacturing an oily preparation which comprises irradiating a triglyceride of saturated middle chain fatty acid(s) with light longer than 290 nm. This process alters the oil to be a solvent in which a selection of 1-alpha-hydroxy-vitamin Ds in the treated triglyceride can be dissolved and remain stable. These 1-hydroxy vitamin D's are either diol or triol compounds which are fundamentally different from vitamin D2 and vitamin D3.
Notwithstanding the above teachings of the prior art, there remains a need for a safe, convenient and efficacious method of administering nutritional or therapeutic amounts of vitamin D to a human being, particularly, a suckling infant. There is also a utility for adults to be able to deliver a dose of vitamin D efficiently by sucking a vitamin supplement from a surface, instead of directly placing the supplement directly into the mouth.